Apparatus for cooling sinter



May 1, 1956 M. L. COVER APPARATUS FOR COOLING SINTER 2 SheetsSheet 1Filed Sept. 29, 1952 n fllw INVENTOR.

MART/N Z. fiovfk BY ""'"l I I 2 A7 May 1, 1956 M. L. COVER ,534

- APPARATUS FOR COOLING SINTER Fil ed Sept. 29, 1352 2 Sheets-Sheet 2INVENTOR.

6 MflAT/A/ z. 601 0? ATTOR/VfYS United States Patent APPARATUS FORCOOLING SINTER Martin L. Cover, Allen Park, Mich.

Application September 29, 1952, Serial No. 312,017

9 Claims. (Cl. 34-174) This invention relates generally to apparatus forsintering materials for use in blast furnaces.

It is well known that to provide a proper blast furnace charge or burdenfine materials such as iron ore, flue dust, necessary fuel in the formof carbon, fine coke and so forth and fine sinter returns are mixed,charged onto pallets of a sintering machine, ignited, and burned by ablast of air drawn through by suction. Then the usually still hot sinteris discharged from the pallet, cooled, and then fed to a blast furnaceat the proper time.

Sintering machines of the Dwight and Lloyd endless track type are wellknown, and in these machines, one of which is shown in the Babb Patent2,441,383, issued May 11, 1948, plurality of pallets are arranged in acontinuously moving machine with wind boxes or suction boxes providedunderneath the pallets during the loading cycle. A suction fan producesa vacuum of from 20 to 30 inches of water in the wind boxes and pullsair down through the mixture forming the sinter bed. The sinter bed issupported by grate bars, and an ignition furnace extending across thesinter bed ignites the material at the top as it passes a point adjacentthe loading station.

The burning of the sinter progresses from top down to the grates and isusually so arranged that it reaches the grates at about the time thatthe sinter is ready for discharge. This means that a portion of thesinter adjacent the grates may have a temperature of 1800 to 2000 F.whereas the portion of the sinter adjacent the top of the bed may befrom around room temperature to 200 F. There is then the problem ofcooling the sinter after it is discharged from the sintering beds.

Since the sinter is to be part of the burden of a blast furnace, it isessential that it have certain characteristics in order to insureuniform and most efiicient operation of the blast furnace. One of thecharacteristics required is a fairly uniform size and suflicientstructural strength to support the overburden. The usual size desired isaround one inch diameter of particles with as little fine material aspossible.

A sinter which leaves a sinter bed in good condition from the point ofview of size and strength may be entirely destroyed by the method ofcooling. The elfect of sudden cooling of the hot sinter with water, forexample, is a destruction of the pieces which are apt to be frangiblefollowing the sintering operation. This destruction can also take placeby too rapid air cooling as when extra wind boxes are provided in thesintering machine. On

the other hand, if the sinter is merely dumped in a pile I 2,743,534Patented May 1, 1956 ice ity to prevent undue piling up of the same andto have a continuous flow of the material with a final deposit from therubber loading belt to the blast furnace stockhouse.

Briefly, the invention includes placing the sinter on a slow moving pantype conveyor where it is exposed to natural circulation of air for aperiod of 10 to 15 minutes. This effectively cools the surface of thesinter so that it can be accumulated, but the interior heat would againheat the sinter to a fairly high temperature when it is placed in apile. Consequently, the sinter is then dumped from the slow movingconveyor to a large stationary bin of around 1,000 ton capacity and airis blown up through the sinter. 1 Since the storage period in the binmay be several hours, this air will cool the sinter to the safetemperature at which it can be handled for burdening the blast furnaceor removal to the stock pile.

The sinter is fed from the bin by means of a rotating table feeder ontoa rubber conveyor and conveyed to bins at the blast furnace. Theinvention contemplates a novel construction of a storage bin whichrequires only a little power to operate and which has few moving partsto wear.

Other objects and features of the invention having to do with details ofconstruction will be apparent in the following description and claims.

Drawings accompany this application, and the various views thereof maybe briefly described as:

Figure 1, a vertical section and diagrammatic lay-out of the variousparts of the cooling apparatus.

Figure 2, a view of a modified cooling bin which may be associateddirectly with a sinter machine.

Figure 3, a plan view of the modified cooler.

Figure 4, a sectional view of the modified cooler showing greater detailof construction.

Figure 5, a sectional view on line 5-5 of Figure 4.

Referring to the drawing, in Figure 1 a sintering machine is shown at Shaving the pallet conveyor 10 passing over wind boxes 12 near thedischarge end of the machine. A hot fines screen 14 sifts the finematerial out of the sinter as it leaves the sintering machine and passesit to a hot fines bin 16 where it is cooled and returned by a conveyor18 to the origin of the sinter mix.

The main bulk of the sinter as it is discharged from the sinteringmachine will deposit onto a pan conveyor C having a series of pallets 20which are continuous and which pass continuously around rollers 22 atopposite ends of the conveyor. This conveyor is preferably about feetlong and will be operated at the rate of about 10 feet per minute. Thesint-er will leave the sintering machine with varymg temperatures, thetop of the sinter on each pallet being from 200 to 400 F. while theportion near the grate may be as high as 1000" F. After passing over theconveyor C the temperature should reduce normally to about 800 F. andthe material will then be dumped into the cooling bin B.

A baffle 30 is provided at the top of the bin to distribute the materialevenly as it dumps into the bin. The bin has a cylindrical portion 32,below which is an outwardly extending conical portion 34. The diameterof the bin then reduces in another conical portion 36 to a bottomcylindrical portion 38. The bin B would probably be roughly 50 feet inheight and 25 feet in diameter in the top cylindrical portion, theconical portions being slightly wider at their point of greatestdiameter. The capacity of this bin would be approximately a thousandtons of sinter.

Below the point 40, which is the juncture of the two conical portions 34and 36, a bustle pipe 42 is placed around the bin having small feedopenings 44 leading into the bin. This pipe will furnish cooling air tothe material in the bin, and it ispositioned at thispoint to co-operatewith the wideningportions of the bin.

As the sinter progresses downwardly and reaches the widening-portion 34it will tend to expand 'andloos'en in its density. This permits theair't'o reach all parts of it and to pass then upward through the bodyofthe sinter, thus insuring complete cooling throughout the bin. A cover50 at the top of the bin in conjunction with the cover 30 preventsviolentair ejection and th'us'preve'nts the'carrying of fine dust outofthe bin.

At the discharge portion 38 of the bin an inciincd baille 54 projectsacross the cylindrical portion just short of a-discharge opening 56. Arotating plate 58 at the bottom of the bin carries the cooled sinterfrom the'discharge opening 56 onto a rubber conveyor belt 60 leading tothe loading point of a blast-furnace or to a stock pile. As the materialreaches the rubber, it will be approximately 200 F. or lower and'can besafely handled by the rubber belt conveyor.

With this installation, it will be seen that the sinter can beeffectively cooled without the'use of any quenching water or quenchingair which has a tendency to break up the sinter lumps. In some cases ithas been the practice to add additional wind boxes to the end of asinter machine simply for the purpose of cooling the sinter. This is anexpensive installation as compared with the simple pan conveyor C andalso has the disadvantage of the too rapid air quench which tendstodestroy the body of the material.

The air which is introduced through the bustle pipe 42 reaches thesinter when it has cooled to a safe temperature and also when it is in alarge enough body that there will-be no sudden chilling and destructivecooling effect on the sinter.

Thus, a fine quality of sinter can be obtained which will furnish anefiicient part of the blast furnace burden, being of sufiicient strengthto sustain the load of the burden and of sutiicient size to permit evendistribution of the chemical reactions in the furnace.

In Figure 2, l have shown a modified cooling bin which may be utilizeddirectly in connection with the end of the sinter unit S.

Referring to the drawing, the grizzlies are sifting devices for thesinter as it leaves the sinter bed and are shown at 70 overlying the hotfines bin 72. Sinter which does not pass through the grizzlies 70 willbe directed to the cooling bin 74 which is constructed with anincreasing tapered wall 76 which terminates in a cylindrical portion 78at the widest point of the bin.

Within the cylindrical portion 78 a tapered portion 80 cooperates withan annular plate 82 to provide an annular passage 84 which is connectedat diametrically opposed points to branch pipes 86 leading to a mainvacuum pipe 88. The bottom section of the cooling bin 74 is formed bytwo flat plates 90 and 92 which are angled downwardly toward the centerof the device, leaving one open quadrant 94. The bottom of the openquadrantis formed partially by the plate 80 and partially by the downchute 96 which provides the outlet for the unit, under which the table100 is rotated to remove the material to a conveyor such as shown at60in Figure 1.

A stop plate 102 is provided to dump'the'material onto the conveyor.Triangular gussetplates 106 support the annular plate 82 and join to thebottom plates 90 and 92. Strut plates 110 are provided on plates 90 and92 leading toward the open quadrant 94. Similarly, downward angled strutplates 112 are provided in the open quadrant over the plate 80.

i The purpose of these strut plates 110 and 112 is to allow the sinterto fill in the spaces betweenthesestruts to form a Wearing bottom .forthe unit so that the extremcly abrasive material Will not wear out thebottom of the bin by constant abrasion. These struts swipestioned todirect the material downwardly toward "the open quadrant 94, where itwill be discharged.

Cooling of the sinter in the bin is accomplished by suction in theannular passage 84 which is transferred to the bin through E pipes shownin section in Figure 4. These E pipes have a central passage 122 whichopens to the annular passage 84. The vertical passages of the E pipesare controlled by dampers 124 and 126. The lower passage of the pipeconnects into the bottom of the unit at 128 and the top connects intothe unit above the widest portion at 130. These E pipesare spaced aroundthe bin as shown in Figures 3 and 5.

With the damper control, it is thus possible to use only the lower pipes128 when the bin is just being filled or is almost empty. As the binfills up the air may be pulled to a greater degree through the openings130 in the bin, the vacuum being produced by the same general fan thatis used for the sinter machine S (Figure 1).

Thus, by cooling with vacuum the dust can be controlled and pulled intoa recovery unit where it can be re-used. This device also has theadvantage that it adds heat to the fines being recovered so that theyare warm as they enter the sintering unit.

The increasing diameter of the bin from the entrance is provided toavoid the abrasive wear above described, and the bottom arrangement isprovided to keep the weightof the load in the bin off from the feedertable.

In the initial operation of the device, wind box cooling of the sintercould be used to start the flow of the sinter to the bin 74. As the binfills'up, the sinter machine could be increased in speed and the sinterwould be cooled very gradually in the bin 74, thus avoiding thequenching action which is detrimental to the sinter when it is cooled inthe sinter wind boxes at the end of the sinter room.

The device described can be installed for much less money than isrequired to install extra wind boxes on a sinter machine for cooling,and the design of. the tank is such that it eliminates the constantreplacement which would otherwise be necessary in a standard funnel-typebin.

With the present unit, six to ten wind boxes on a sinter unit would berequired to produce 1,000 to 1,500 tons of sinter per day, whereas whenthe cooling is accomplished with a sinter machine for the sameproduction, sixteen wind boxes would be necessary and an expensiverotary cooler would have to be installed. A suitable diameter for'thebin would be about fifteen feet, the bin having an overall height ofapproximately sixteen feet. The E pipes 120 would preferably beapproximately iiiiie inches india rriet'er with about sixteen spacedaround the unit.

This application is a continuation-impart of my copending applicationSerial No. 138,488, filed January 13, 1950, and now abandoned.

WhatI claim is:

1. LA sinter cooling bin which comprises a relatively large, circularbin having an open top and side walls tapering outwardly fromthe opentop, sinter supporting means at the bottom of the bin comprisingstationary plates angled to a discharge opening, and means on saidplates also angled toward said opening'to collect a compacted layer ofsinter material to provide a wearing surface for the bottom of the bin,said surface angling toward "said opening.

2. A cooling bin for sinter discharged from a sinter machine whichcomprises a large bin circular in cross section having an open top toreceive sinter, and side walls tapering from said open top outwardly anddownwardly toward the mid-portion of the bin, means forming a dischargeopening at one quadrant of the bottom portion of said bin, and bottomplate means extending from the side walls of said 'bin toward saiddischarge opening, vertical jstr ut mean s on said bottom plate meansextending from the side walls to saiddiseharge opening ito'caus'e acompaction of sinter to create "a wearing surface for the bottom of thebin, means forming a suction air passage between the side walls of saidbin and said bottom plates, and means for feeding air from said binabove and below said suctioii air passage to said passage to providecooling of the contents of the bin.

3. In a sinter cooling bin, a bottom formed by supporting plates angledfrom the outside of the bin to a discharge opening at the bottom of thebin, and strut means extending along said plates substantially in adirection toward the discharge opening, the top edges of the strutslying at a greater angle to horizontal than the supporting plates toprovide open-topped pockets for a compacted layer of sinter material tocreate a wear bottom for said bin, said wear bottom to lie along the topedges of said plates and tapering toward said opening.

4. A sinter cooling bin comprising a circular open top, retaining meanstapered outwardly and downwardly from the top to a mid-portion thereof,means forming a conical inwardly directed wall centrally of said bin andserving also to create one wall of an annular suction passage within theconfines of said bin, an annular plate means forming a third wall forsaid annular passage, bottom plate means completing said bin anglingdownwardly toward one segment of the bin, means forming an outletpassage at said segment, and means forming air passage outlets for saidbin above and below said annular passage and connected thereto wherebysuction created in said annular passage will draw air from the inlet andthe outlet of said bin to said passage through sinter material withinthe bin.

5. A sinter cooling bin as defined in claim 4 in which guide plate meansare vertically disposed on said conical plate means and said bottomplate means extending toward said discharge opening to provide pocketsfor a compacted layer of sinter material passing through said bin.

6. A sinter cooling apparatus which comprises a relatively long, open,continuous conveyor having one end positioned to receive sinter on thetop pass of the conveyor from a continuous sintering machine, theconveyor extending upwardly at an angle from the receiving end to adischarging end, a cooling bin at the discharging end comprising asubstantially cylindrical container open at the top end having a widenedportion adjacent the midsection to provide a substantially increasedarea at that portion, a bustle pipe for injecting air into the binconnected to the bin at spaced intervals around the circumferencethereof, a narrowed portion at the discharge end of said bin having aside opening, a bafile plate angled in the bottom portion to saidopening, and a rotating discharge plate at the discharge end of said binunderlying said plate except at said opening to carry cooled sinter fromthe bin through said opening.

7. In a sinter cooling apparatus of the type to receive sinter from acontinuous, open, conveyor, a cooling bin positioned to receivepartially cooled sinter from the top pass of the conveyor comprising astationary cylindrical container open at the top and bottom and having asubstantially widened portion centrally located adjacent a plurality ofcircumferentially spaced air inlets for cooling air.

8. A sinter cooler as defined in claim 7 in which the bin issubstantially narrowed at the bottom to support the load of the contentson the walls of the bin, an opening formed in the side of said narrowedportion, a load baflle angled in said narrowed portion toward saidopening from a higher point in said bin, and a rotating plate at thebottom of said opening underlying said plate except at said opening tocarry sinter from said bin out of said opening.

9. Apparatus'for the cooling of hot sinter with air flow, whichcomprises, a relatively large, open-topped bin substantially circular inhorizontal section and having a top entrance, said bin having asubstantially cylindrical shape extending downwardly from the open topabout one-half the vertical height of the bin, an intermediate sectiondirectly below said' cylindrical section having conical frustum shapeflaring outwardly and downwardly to a maximum diameter terminating aboutonethird vertical height from the bottom of the bin, the remainder ofthe bin comprising a conical frustum section extending inwardly anddownwardly from the maximum diameter to a discharge opening at thebottom, an air flow distributor means around said bin directly adjacentthe top of the lower conical frustum section at a diameter greater thanthe upper cylindrical portion for introducing cooling air atcircumferentially spaced points into the bin directly below the maximumdiameter thereof into a charge of sinter within the tank to cool thesame prior to discharge from the bin.

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